Sandwich slinger Potbelly (NASDAQ:PBPB) made its public debut on the markets this morning, zooming up more than 130% after the opening bell.

Potbelly was founded in 1977 in Chicago in a former antique shop. In 1996, the founder sold it to entrepreneur Bryant Keil, who grew the company to hundreds of locations before stepping down from the CEO role in 2008. Potbelly's presiding CEO, Aylwin Lewis, has been at the helm ever since.

The shares were initially priced at $14, but opened at $28.79 and have only climbed from there. Motley Fool analyst Ron Gross doesn't like some of the mechanics of the IPO, but he thinks the starting valuation was very reasonable, which is evidenced by the large pop in the stock's price. Ron thinks that after the pop, shares look a little expensive. He notes that Potbelly expects to grow its store count by 10% a year, which is solid growth, so Ron's keeping an eye on Potbelly.

Erin Kennedy has no position in any stocks mentioned. Ron Gross has no position in any stocks mentioned. The Motley Fool recommends Chipotle Mexican Grill. The Motley Fool owns shares of Chipotle Mexican Grill. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.